Fish prompt with Git current branch name

fish_prompt.fish

function fish_prompt --description 'Write out the prompt'
  set -l color_cwd
  set -l suffix
  switch "$USER"
    case root toor
      if set -q fish_color_cwd_root
        set color_cwd $fish_color_cwd_root
      else
        set color_cwd $fish_color_cwd
      end

      set suffix '#'
    case '*'
      set color_cwd $fish_color_cwd
      set suffix '>'
  end

  set -l color_branch cyan
  set -l branch_name (git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/')

  echo -n -s "$USER" @ (prompt_hostname) ' ' (set_color $color_cwd) (prompt_pwd) (set_color $color_branch) "$branch_name" (set_color normal) "$suffix "
end